The prior art discloses numerous methods of obtaining hydrocarbon gases from carbonaceous materials, such as those proposed in U.S. Pat. No. 3,775,072, wherein the organic material is reacted under pressure with steam; U.S. Pat. No. 2,759,677 which provides for use of steam generated in the process for reaction with waste materials; U.S. Pat. No. 3,776,150 which uses a fluidized bed for methanation reactions; U.S. Pat. No. 3,817,724 wherein oxygen-free recycle gases are introduced into the combustion zone; and U.S. Pat. No. 3,817,725 wherein methanated gases are recycled to a combustion zone for purposes of transferring sensible heat and increasing methane content in the product.
Many hydrogenation, gasification and methanation processes utilize metals as catalysts. For example, U.S. Pat. Nos. 3,759,677 and 3,817,725 disclose alkali carbonates as preferred gasification catalysts. U.S. Pat. No. 3,817,725 further uses Group VIII metals, such as nickel, either as oxides or sulfides, as catalysts in a methanation zone having a temperature of 500.degree.-1000.degree. F. Catalysts consisting of single metals, including oxides, sulfides or carbonates or mixtures of these, selected from Groups IB, VIB and VIII, in addition to an alkali-type promoter from Group IA, IIA and VII rare earths, are used in a two stage gasification and methanation process of U.S. Pat. No. 3,904,386. U.S. Pat. No. 3,594,305 teaches the use of a two component catalyst system for the hydrogasification of coal at a temperature of 750.degree.-800.degree. F., wherein the first catalyst is selected from Group VIII and is preferably an alloy such as cobalt/molybdenum, nickel/tungsten or nickel/molybdenum and the second catalyst is a noble metal. U.S. Pat. No. 3,505,204 obtains hydrocarbons from carbonaceous materials in a single reactor having a temperature of 800.degree.-1200.degree. F. by using a two component catalyst comprising an alkali metal or alkaline earth metal in conjunction with a Group VIII metal. U.S. Pat. No. 3,847,567 utilizes a Group VIII or an alkali metal as a methane reduction catalyst in a gas reformer of a coal hydrogasification process. U.S. Pat. No. 2,629,728 discloses the use of an iron nitrite catalyst to hydrogenate carbon oxides. Additionally, iron and iron oxide are taught as catalysts in a methanation zone having a temperature of 800.degree.-1200.degree. F. for the production of gaseous fuels by synthesis in U.S. Pat. No. 2,543,759. U.S. Pat. No. 1,495,776 teaches a catalytic process for converting carbonaceous material into gases. Lime is the preferred catalyst; however, other reagents such as calcium, alumina, magnesia, silica, iron, nickel or copper and mixtures thereof may be used.